walkero
/
cppcheck
1
0
Fork 0
Code Issues Pull Requests Projects Releases 1 Wiki Activity

Refactoring checks of overlapping conditions in if and else-if

This commit is contained in:
Daniel Marjamäki 2014-04-03 19:35:50 +02:00
parent 749117a7ff
commit 8dcb3bae47
5 changed files with 132 additions and 205 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

77
lib/checkassignif.cpp
View File

@ -249,9 +249,44 @@ void CheckAssignIf::comparisonError(const Token *tok, const std::string &bitop,
reportError(tok, Severity::style, "comparisonError", errmsg);
}
extern bool isSameExpression(const Token *tok1, const Token *tok2, const std::set<std::string> &constFunctions);
static bool isOverlappingCond(const Token * const cond1, const Token * const cond2, const std::set<std::string> &constFunctions)
{
if (!cond1 || !cond2)
return false;
// same expressions
if (isSameExpression(cond1,cond2,constFunctions))
return true;
// bitwise overlap for example 'x&7' and 'x==1'
if (cond1->str() == "&" && cond1->astOperand1() && cond2->astOperand2()) {
const Token *expr1 = cond1->astOperand1();
const Token *num1 = cond1->astOperand2();
if (!num1->isNumber())
std::swap(expr1,num1);
if (!num1->isNumber() || MathLib::isNegative(num1->str()))
return false;
if (!Token::Match(cond2, "&|==") || !cond2->astOperand1() || !cond2->astOperand2())
return false;
const Token *expr2 = cond2->astOperand1();
const Token *num2 = cond2->astOperand2();
if (!num2->isNumber())
std::swap(expr2,num2);
if (!num2->isNumber() || MathLib::isNegative(num2->str()))
return false;
if (!isSameExpression(expr1,expr2,constFunctions))
return false;
const MathLib::bigint value1 = MathLib::toLongNumber(num1->str());
const MathLib::bigint value2 = MathLib::toLongNumber(num2->str());
return ((value1 & value2) == value2);
}
return false;
}
void CheckAssignIf::multiCondition()
@ -262,37 +297,23 @@ void CheckAssignIf::multiCondition()
const SymbolDatabase* const symbolDatabase = _tokenizer->getSymbolDatabase();
for (std::list<Scope>::const_iterator i = symbolDatabase->scopeList.begin(); i != symbolDatabase->scopeList.end(); ++i) {
if (i->type == Scope::eIf && Token::Match(i->classDef, "if ( %var% & %num% ) {")) {
const Token* const tok = i->classDef;
const unsigned int varid(tok->tokAt(2)->varId());
if (varid == 0)
continue;
if (i->type != Scope::eIf || !Token::simpleMatch(i->classDef, "if ("))
continue;
const MathLib::bigint num1 = MathLib::toLongNumber(tok->strAt(4));
if (num1 < 0)
continue;
const Token * const cond1 = i->classDef->next()->astOperand2();
const Token *tok2 = tok->linkAt(6);
while (Token::simpleMatch(tok2, "} else { if (")) {
// Goto '('
const Token * const opar = tok2->tokAt(4);
const Token * tok2 = i->classDef->next();
while (tok2) {
tok2 = tok2->link();
if (!Token::simpleMatch(tok2, ") {"))
break;
tok2 = tok2->linkAt(1);
if (!Token::simpleMatch(tok2, "} else { if ("))
break;
tok2 = tok2->tokAt(4);
// tok2: skip if-block
tok2 = opar->link();
if (Token::simpleMatch(tok2, ") {"))
tok2 = tok2->next()->link();
// check condition..
if (Token::Match(opar, "( %varid% ==|& %num% &&|%oror%|)", varid)) {
const MathLib::bigint num2 = MathLib::toLongNumber(opar->strAt(3));
if (num2 < 0)
continue;
if ((num1 & num2) == num2) {
multiConditionError(opar, tok->linenr());
}
}
}
if (isOverlappingCond(cond1, tok2->astOperand2(), _settings->library.functionpure))
multiConditionError(tok2, cond1->linenr());
}
}
}

66
lib/checkother.cpp
View File

@ -72,7 +72,7 @@ static bool isConstExpression(const Token *tok, const std::set<std::string> &con
return isConstExpression(tok->astOperand1(),constFunctions) && isConstExpression(tok->astOperand2(),constFunctions);
}
static bool isSameExpression(const Token *tok1, const Token *tok2, const std::set<std::string> &constFunctions)
bool isSameExpression(const Token *tok1, const Token *tok2, const std::set<std::string> &constFunctions)
{
if (tok1 == nullptr && tok2 == nullptr)
return true;
@ -166,6 +166,7 @@ static bool isOppositeCond(const Token * const cond1, const Token * const cond2,
(comp1 == ">=" && comp2 == "<="));
}
//----------------------------------------------------------------------------------
// The return value of fgetc(), getc(), ungetc(), getchar() etc. is an integer value.
// If this return value is stored in a character variable and then compared
@ -2559,69 +2560,6 @@ static bool expressionHasSideEffects(const Token *first, const Token *last)
return false;
}
void CheckOther::checkDuplicateIf()
{
if (!_settings->isEnabled("style"))
return;
const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase();
for (std::list<Scope>::const_iterator scope = symbolDatabase->scopeList.begin(); scope != symbolDatabase->scopeList.end(); ++scope) {
const Token* const tok = scope->classDef;
// only check if statements
if (scope->type != Scope::eIf || !tok)
continue;
std::map<std::string, const Token*> expressionMap;
// get the expression from the token stream
std::string expression = tok->tokAt(2)->stringifyList(tok->next()->link());
// save the expression and its location
expressionMap[expression] = tok;
// find the next else if (...) statement
const Token *tok1 = scope->classEnd;
// check all the else if (...) statements
while (Token::simpleMatch(tok1, "} else { if (") &&
Token::simpleMatch(tok1->linkAt(4), ") {")) {
int conditionIndex=(tok1->strAt(3)=="(") ? 3 : 4;
// get the expression from the token stream
expression = tok1->tokAt(conditionIndex+1)->stringifyList(tok1->linkAt(conditionIndex));
// try to look up the expression to check for duplicates
std::map<std::string, const Token *>::iterator it = expressionMap.find(expression);
// found a duplicate
if (it != expressionMap.end()) {
// check for expressions that have side effects and ignore them
if (!expressionHasSideEffects(tok1->tokAt(conditionIndex+1), tok1->linkAt(conditionIndex)->previous()))
duplicateIfError(it->second, tok1->next());
}
// not a duplicate expression so save it and its location
else
expressionMap[expression] = tok1->next();
// find the next else if (...) statement
tok1 = tok1->linkAt(conditionIndex)->next()->link();
}
}
}
void CheckOther::duplicateIfError(const Token *tok1, const Token *tok2)
{
std::list<const Token *> toks;
toks.push_back(tok2);
toks.push_back(tok1);
reportError(toks, Severity::style, "duplicateIf", "Duplicate conditions in 'if' and related 'else if'.\n"
"Duplicate conditions in 'if' and related 'else if'. This is suspicious and might indicate "
"a cut and paste or logic error. Please examine this code carefully to determine "
"if it is correct.");
}
//-----------------------------------------------------------------------------
// check for duplicate code in if and else branches
// if (a) { b = true; } else { b = true; }

6
lib/checkother.h
View File

@ -30,6 +30,10 @@ class Token;
class Function;
class Variable;
/** Is expressions same? */
bool isSameExpression(const Token *tok1, const Token *tok2, const std::set<std::string> &constFunctions);
/// @addtogroup Checks
/// @{
@ -61,7 +65,6 @@ public:
checkOther.checkRedundantAssignmentInSwitch();
checkOther.checkSuspiciousCaseInSwitch();
checkOther.checkSelfAssignment();
checkOther.checkDuplicateIf();
checkOther.checkDuplicateBranch();
checkOther.checkDuplicateExpression();
checkOther.checkUnreachableCode();
@ -382,7 +385,6 @@ private:
c.incorrectStringCompareError(0, "substr", "\"Hello World\"");
c.suspiciousStringCompareError(0, "foo");
c.incorrectStringBooleanError(0, "\"Hello World\"");
c.duplicateIfError(0, 0);
c.duplicateBranchError(0, 0);
c.duplicateExpressionError(0, 0, "&&");
c.alwaysTrueFalseStringCompareError(0, "str1", "str2");

77
test/testassignif.cpp
View File

@ -37,6 +37,7 @@ private:
TEST_CASE(mismatchingBitAnd); // overlapping bitmasks
TEST_CASE(compare); // mismatching LHS/RHS in comparison
TEST_CASE(multicompare); // mismatching comparisons
TEST_CASE(duplicateIf); // duplicate conditions in if and else-if
}
void check(const char code[]) {
@ -283,6 +284,82 @@ private:
"}");
ASSERT_EQUALS("[test.cpp:4]: (style) Expression is always false because 'else if' condition matches previous condition at line 3.\n", errout.str());
}
void duplicateIf() {
check("void f(int a, int &b) {\n"
" if (a) { b = 1; }\n"
" else { if (a) { b = 2; } }\n"
"}");
ASSERT_EQUALS("[test.cpp:3]: (style) Expression is always false because 'else if' condition matches previous condition at line 2.\n", errout.str());
check("void f(int a, int &b) {\n"
" if (a) { b = 1; }\n"
" else { if (a) { b = 2; } }\n"
"}");
ASSERT_EQUALS("[test.cpp:3]: (style) Expression is always false because 'else if' condition matches previous condition at line 2.\n", errout.str());
check("void f(int a, int &b) {\n"
" if (a == 1) { b = 1; }\n"
" else { if (a == 2) { b = 2; }\n"
" else { if (a == 1) { b = 3; } } }\n"
"}");
ASSERT_EQUALS("[test.cpp:4]: (style) Expression is always false because 'else if' condition matches previous condition at line 2.\n", errout.str());
check("void f(int a, int &b) {\n"
" if (a == 1) { b = 1; }\n"
" else { if (a == 2) { b = 2; }\n"
" else { if (a == 2) { b = 3; } } }\n"
"}");
ASSERT_EQUALS("[test.cpp:4]: (style) Expression is always false because 'else if' condition matches previous condition at line 3.\n", errout.str());
check("void f(int a, int &b) {\n"
" if (a++) { b = 1; }\n"
" else { if (a++) { b = 2; }\n"
" else { if (a++) { b = 3; } } }\n"
"}");
ASSERT_EQUALS("", errout.str());
check("void f(int a, int &b) {\n"
" if (!strtok(NULL," ")) { b = 1; }\n"
" else { if (!strtok(NULL," ")) { b = 2; } }\n"
"}");
ASSERT_EQUALS("", errout.str());
check("void f(int a, int &b) {\n"
" x = x / 2;\n"
" if (x < 100) { b = 1; }\n"
" else { x = x / 2; if (x < 100) { b = 2; } }\n"
"}");
ASSERT_EQUALS("", errout.str());
check("void f(int i) {\n"
" if(i == 0x02e2000000 || i == 0xa0c6000000)\n"
" foo(i);\n"
"}");
ASSERT_EQUALS("", errout.str());
// ticket 3689 ( avoid false positive )
check("int fitInt(long long int nValue){\n"
" if( nValue < 0x7fffffffLL )\n"
" {\n"
" return 32;\n"
" }\n"
" if( nValue < 0x7fffffffffffLL )\n"
" {\n"
" return 48;\n"
" }\n"
" else {\n"
" if( nValue < 0x7fffffffffffffffLL )\n"
" {\n"
" return 64;\n"
" } else\n"
" {\n"
" return -1;\n"
" }\n"
" }\n"
"}");
ASSERT_EQUALS("", errout.str());
}
};
REGISTER_TEST(TestAssignIf)

111
test/testother.cpp
View File

@ -153,8 +153,6 @@ private:
TEST_CASE(incorrectStringCompare);
TEST_CASE(duplicateIf);
TEST_CASE(duplicateIf1); // ticket 3689
TEST_CASE(duplicateBranch);
TEST_CASE(duplicateBranch1); // tests extracted by http://www.viva64.com/en/b/0149/ ( Comparison between PVS-Studio and cppcheck ): Errors detected in Quake 3: Arena by PVS-Studio: Fragement 2
TEST_CASE(duplicateBranch2); // empty macro
@ -4502,91 +4500,6 @@ private:
ASSERT_EQUALS("", errout.str());
}
void duplicateIf() {
check("void f(int a, int &b) {\n"
" if (a) { b = 1; }\n"
" else { if (a) { b = 2; } }\n"
"}");
ASSERT_EQUALS("[test.cpp:3] -> [test.cpp:2]: (style) Duplicate conditions in 'if' and related 'else if'.\n", errout.str());
check("void f(int a, int &b) {\n"
" if (a) { b = 1; }\n"
" else { if (a) { b = 2; } }\n"
"}");
ASSERT_EQUALS("[test.cpp:3] -> [test.cpp:2]: (style) Duplicate conditions in 'if' and related 'else if'.\n", errout.str());
check("void f(int a, int &b) {\n"
" if (a == 1) { b = 1; }\n"
" else { if (a == 2) { b = 2; }\n"
" else { if (a == 1) { b = 3; } } }\n"
"}");
ASSERT_EQUALS("[test.cpp:4] -> [test.cpp:2]: (style) Duplicate conditions in 'if' and related 'else if'.\n", errout.str());
check("void f(int a, int &b) {\n"
" if (a == 1) { b = 1; }\n"
" else { if (a == 2) { b = 2; }\n"
" else { if (a == 2) { b = 3; } } }\n"
"}");
ASSERT_EQUALS("[test.cpp:4] -> [test.cpp:3]: (style) Duplicate conditions in 'if' and related 'else if'.\n", errout.str());
check("void f(int a, int &b) {\n"
" if (a == 1) {\n"
" b = 1;\n"
" if (b == 1) { }\n" // condition is always true. must skip simplifications
" else if (b == 1) { }\n"
" } else if (a == 2) { b = 2; }\n"
" else if (a == 2) { b = 3; }\n"
"}", 0, false, false, false, false);
ASSERT_EQUALS("[test.cpp:7] -> [test.cpp:6]: (style) Duplicate conditions in 'if' and related 'else if'.\n"
"[test.cpp:5] -> [test.cpp:4]: (style) Duplicate conditions in 'if' and related 'else if'.\n", errout.str());
check("void f(int a, int &b) {\n"
" if (a++) { b = 1; }\n"
" else { if (a++) { b = 2; }\n"
" else { if (a++) { b = 3; } } }\n"
"}");
ASSERT_EQUALS("", errout.str());
check("void f(int a, int &b) {\n"
" if (!strtok(NULL," ")) { b = 1; }\n"
" else { if (!strtok(NULL," ")) { b = 2; } }\n"
"}");
ASSERT_EQUALS("", errout.str());
check("void f(int a, int &b) {\n"
" x = x / 2;\n"
" if (x < 100) { b = 1; }\n"
" else { x = x / 2; if (x < 100) { b = 2; } }\n"
"}");
ASSERT_EQUALS("", errout.str());
check("void f(int i) {\n"
" if(i == 0x02e2000000 || i == 0xa0c6000000)\n"
" foo(i);\n"
"}");
ASSERT_EQUALS("", errout.str());
check("void f(const std::string &token)\n"
"{\n"
" if( token == \"C\")\n"
" {\n"
" std::cout << \"C\";\n"
" }\n"
" else { if ( token == \"A\" )\n"
" {\n"
" std::cout << \"A\";\n"
" }\n"
" else { if ( token == \"A\" )\n"
" {\n"
" std::cout << \"A\";\n"
" }\n"
" }\n"
" }\n"
"}");
ASSERT_EQUALS("[test.cpp:11] -> [test.cpp:7]: (style) Duplicate conditions in 'if' and related 'else if'.\n", errout.str());
}
void duplicateBranch() {
check("void f(int a, int &b) {\n"
" if (a)\n"
@ -4818,30 +4731,6 @@ private:
ASSERT_EQUALS("", errout.str());
}
void duplicateIf1() { // ticket 3689 ( avoid false positive )
check("int fitInt(long long int nValue){\n"
" if( nValue < 0x7fffffffLL )\n"
" {\n"
" return 32;\n"
" }\n"
" if( nValue < 0x7fffffffffffLL )\n"
" {\n"
" return 48;\n"
" }\n"
" else {\n"
" if( nValue < 0x7fffffffffffffffLL )\n"
" {\n"
" return 64;\n"
" } else\n"
" {\n"
" return -1;\n"
" }\n"
" }\n"
"}");
ASSERT_EQUALS("", errout.str());
}
void duplicateExpression2() { // check if float is NaN or Inf
check("int f(long double ldbl, double dbl, float flt) {\n" // ticket #2730
" if (ldbl != ldbl) have_nan = 1;\n"